1 /* 2 * kernel userspace event delivery 3 * 4 * Copyright (C) 2004 Red Hat, Inc. All rights reserved. 5 * Copyright (C) 2004 Novell, Inc. All rights reserved. 6 * Copyright (C) 2004 IBM, Inc. All rights reserved. 7 * 8 * Licensed under the GNU GPL v2. 9 * 10 * Authors: 11 * Robert Love <rml@novell.com> 12 * Kay Sievers <kay.sievers@vrfy.org> 13 * Arjan van de Ven <arjanv@redhat.com> 14 * Greg Kroah-Hartman <greg@kroah.com> 15 */ 16 17 #include <linux/spinlock.h> 18 #include <linux/string.h> 19 #include <linux/kobject.h> 20 #include <linux/export.h> 21 #include <linux/kmod.h> 22 #include <linux/slab.h> 23 #include <linux/socket.h> 24 #include <linux/skbuff.h> 25 #include <linux/netlink.h> 26 #include <linux/uuid.h> 27 #include <linux/ctype.h> 28 #include <net/sock.h> 29 #include <net/net_namespace.h> 30 31 32 u64 uevent_seqnum; 33 #ifdef CONFIG_UEVENT_HELPER 34 char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH; 35 #endif 36 #ifdef CONFIG_NET 37 struct uevent_sock { 38 struct list_head list; 39 struct sock *sk; 40 }; 41 static LIST_HEAD(uevent_sock_list); 42 #endif 43 44 /* This lock protects uevent_seqnum and uevent_sock_list */ 45 static DEFINE_MUTEX(uevent_sock_mutex); 46 47 /* the strings here must match the enum in include/linux/kobject.h */ 48 static const char *kobject_actions[] = { 49 [KOBJ_ADD] = "add", 50 [KOBJ_REMOVE] = "remove", 51 [KOBJ_CHANGE] = "change", 52 [KOBJ_MOVE] = "move", 53 [KOBJ_ONLINE] = "online", 54 [KOBJ_OFFLINE] = "offline", 55 }; 56 57 static int kobject_action_type(const char *buf, size_t count, 58 enum kobject_action *type, 59 const char **args) 60 { 61 enum kobject_action action; 62 size_t count_first; 63 const char *args_start; 64 int ret = -EINVAL; 65 66 if (count && (buf[count-1] == '\n' || buf[count-1] == '\0')) 67 count--; 68 69 if (!count) 70 goto out; 71 72 args_start = strnchr(buf, count, ' '); 73 if (args_start) { 74 count_first = args_start - buf; 75 args_start = args_start + 1; 76 } else 77 count_first = count; 78 79 for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) { 80 if (strncmp(kobject_actions[action], buf, count_first) != 0) 81 continue; 82 if (kobject_actions[action][count_first] != '\0') 83 continue; 84 if (args) 85 *args = args_start; 86 *type = action; 87 ret = 0; 88 break; 89 } 90 out: 91 return ret; 92 } 93 94 static const char *action_arg_word_end(const char *buf, const char *buf_end, 95 char delim) 96 { 97 const char *next = buf; 98 99 while (next <= buf_end && *next != delim) 100 if (!isalnum(*next++)) 101 return NULL; 102 103 if (next == buf) 104 return NULL; 105 106 return next; 107 } 108 109 static int kobject_action_args(const char *buf, size_t count, 110 struct kobj_uevent_env **ret_env) 111 { 112 struct kobj_uevent_env *env = NULL; 113 const char *next, *buf_end, *key; 114 int key_len; 115 int r = -EINVAL; 116 117 if (count && (buf[count - 1] == '\n' || buf[count - 1] == '\0')) 118 count--; 119 120 if (!count) 121 return -EINVAL; 122 123 env = kzalloc(sizeof(*env), GFP_KERNEL); 124 if (!env) 125 return -ENOMEM; 126 127 /* first arg is UUID */ 128 if (count < UUID_STRING_LEN || !uuid_is_valid(buf) || 129 add_uevent_var(env, "SYNTH_UUID=%.*s", UUID_STRING_LEN, buf)) 130 goto out; 131 132 /* 133 * the rest are custom environment variables in KEY=VALUE 134 * format with ' ' delimiter between each KEY=VALUE pair 135 */ 136 next = buf + UUID_STRING_LEN; 137 buf_end = buf + count - 1; 138 139 while (next <= buf_end) { 140 if (*next != ' ') 141 goto out; 142 143 /* skip the ' ', key must follow */ 144 key = ++next; 145 if (key > buf_end) 146 goto out; 147 148 buf = next; 149 next = action_arg_word_end(buf, buf_end, '='); 150 if (!next || next > buf_end || *next != '=') 151 goto out; 152 key_len = next - buf; 153 154 /* skip the '=', value must follow */ 155 if (++next > buf_end) 156 goto out; 157 158 buf = next; 159 next = action_arg_word_end(buf, buf_end, ' '); 160 if (!next) 161 goto out; 162 163 if (add_uevent_var(env, "SYNTH_ARG_%.*s=%.*s", 164 key_len, key, (int) (next - buf), buf)) 165 goto out; 166 } 167 168 r = 0; 169 out: 170 if (r) 171 kfree(env); 172 else 173 *ret_env = env; 174 return r; 175 } 176 177 /** 178 * kobject_synth_uevent - send synthetic uevent with arguments 179 * 180 * @kobj: struct kobject for which synthetic uevent is to be generated 181 * @buf: buffer containing action type and action args, newline is ignored 182 * @count: length of buffer 183 * 184 * Returns 0 if kobject_synthetic_uevent() is completed with success or the 185 * corresponding error when it fails. 186 */ 187 int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count) 188 { 189 char *no_uuid_envp[] = { "SYNTH_UUID=0", NULL }; 190 enum kobject_action action; 191 const char *action_args; 192 struct kobj_uevent_env *env; 193 const char *msg = NULL, *devpath; 194 int r; 195 196 r = kobject_action_type(buf, count, &action, &action_args); 197 if (r) { 198 msg = "unknown uevent action string\n"; 199 goto out; 200 } 201 202 if (!action_args) { 203 r = kobject_uevent_env(kobj, action, no_uuid_envp); 204 goto out; 205 } 206 207 r = kobject_action_args(action_args, 208 count - (action_args - buf), &env); 209 if (r == -EINVAL) { 210 msg = "incorrect uevent action arguments\n"; 211 goto out; 212 } 213 214 if (r) 215 goto out; 216 217 r = kobject_uevent_env(kobj, action, env->envp); 218 kfree(env); 219 out: 220 if (r) { 221 devpath = kobject_get_path(kobj, GFP_KERNEL); 222 printk(KERN_WARNING "synth uevent: %s: %s", 223 devpath ?: "unknown device", 224 msg ?: "failed to send uevent"); 225 kfree(devpath); 226 } 227 return r; 228 } 229 230 #ifdef CONFIG_NET 231 static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data) 232 { 233 struct kobject *kobj = data, *ksobj; 234 const struct kobj_ns_type_operations *ops; 235 236 ops = kobj_ns_ops(kobj); 237 if (!ops && kobj->kset) { 238 ksobj = &kobj->kset->kobj; 239 if (ksobj->parent != NULL) 240 ops = kobj_ns_ops(ksobj->parent); 241 } 242 243 if (ops && ops->netlink_ns && kobj->ktype->namespace) { 244 const void *sock_ns, *ns; 245 ns = kobj->ktype->namespace(kobj); 246 sock_ns = ops->netlink_ns(dsk); 247 return sock_ns != ns; 248 } 249 250 return 0; 251 } 252 #endif 253 254 #ifdef CONFIG_UEVENT_HELPER 255 static int kobj_usermode_filter(struct kobject *kobj) 256 { 257 const struct kobj_ns_type_operations *ops; 258 259 ops = kobj_ns_ops(kobj); 260 if (ops) { 261 const void *init_ns, *ns; 262 ns = kobj->ktype->namespace(kobj); 263 init_ns = ops->initial_ns(); 264 return ns != init_ns; 265 } 266 267 return 0; 268 } 269 270 static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem) 271 { 272 int len; 273 274 len = strlcpy(&env->buf[env->buflen], subsystem, 275 sizeof(env->buf) - env->buflen); 276 if (len >= (sizeof(env->buf) - env->buflen)) { 277 WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n"); 278 return -ENOMEM; 279 } 280 281 env->argv[0] = uevent_helper; 282 env->argv[1] = &env->buf[env->buflen]; 283 env->argv[2] = NULL; 284 285 env->buflen += len + 1; 286 return 0; 287 } 288 289 static void cleanup_uevent_env(struct subprocess_info *info) 290 { 291 kfree(info->data); 292 } 293 #endif 294 295 /** 296 * kobject_uevent_env - send an uevent with environmental data 297 * 298 * @kobj: struct kobject that the action is happening to 299 * @action: action that is happening 300 * @envp_ext: pointer to environmental data 301 * 302 * Returns 0 if kobject_uevent_env() is completed with success or the 303 * corresponding error when it fails. 304 */ 305 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, 306 char *envp_ext[]) 307 { 308 struct kobj_uevent_env *env; 309 const char *action_string = kobject_actions[action]; 310 const char *devpath = NULL; 311 const char *subsystem; 312 struct kobject *top_kobj; 313 struct kset *kset; 314 const struct kset_uevent_ops *uevent_ops; 315 int i = 0; 316 int retval = 0; 317 #ifdef CONFIG_NET 318 struct uevent_sock *ue_sk; 319 #endif 320 321 pr_debug("kobject: '%s' (%p): %s\n", 322 kobject_name(kobj), kobj, __func__); 323 324 /* search the kset we belong to */ 325 top_kobj = kobj; 326 while (!top_kobj->kset && top_kobj->parent) 327 top_kobj = top_kobj->parent; 328 329 if (!top_kobj->kset) { 330 pr_debug("kobject: '%s' (%p): %s: attempted to send uevent " 331 "without kset!\n", kobject_name(kobj), kobj, 332 __func__); 333 return -EINVAL; 334 } 335 336 kset = top_kobj->kset; 337 uevent_ops = kset->uevent_ops; 338 339 /* skip the event, if uevent_suppress is set*/ 340 if (kobj->uevent_suppress) { 341 pr_debug("kobject: '%s' (%p): %s: uevent_suppress " 342 "caused the event to drop!\n", 343 kobject_name(kobj), kobj, __func__); 344 return 0; 345 } 346 /* skip the event, if the filter returns zero. */ 347 if (uevent_ops && uevent_ops->filter) 348 if (!uevent_ops->filter(kset, kobj)) { 349 pr_debug("kobject: '%s' (%p): %s: filter function " 350 "caused the event to drop!\n", 351 kobject_name(kobj), kobj, __func__); 352 return 0; 353 } 354 355 /* originating subsystem */ 356 if (uevent_ops && uevent_ops->name) 357 subsystem = uevent_ops->name(kset, kobj); 358 else 359 subsystem = kobject_name(&kset->kobj); 360 if (!subsystem) { 361 pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the " 362 "event to drop!\n", kobject_name(kobj), kobj, 363 __func__); 364 return 0; 365 } 366 367 /* environment buffer */ 368 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); 369 if (!env) 370 return -ENOMEM; 371 372 /* complete object path */ 373 devpath = kobject_get_path(kobj, GFP_KERNEL); 374 if (!devpath) { 375 retval = -ENOENT; 376 goto exit; 377 } 378 379 /* default keys */ 380 retval = add_uevent_var(env, "ACTION=%s", action_string); 381 if (retval) 382 goto exit; 383 retval = add_uevent_var(env, "DEVPATH=%s", devpath); 384 if (retval) 385 goto exit; 386 retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem); 387 if (retval) 388 goto exit; 389 390 /* keys passed in from the caller */ 391 if (envp_ext) { 392 for (i = 0; envp_ext[i]; i++) { 393 retval = add_uevent_var(env, "%s", envp_ext[i]); 394 if (retval) 395 goto exit; 396 } 397 } 398 399 /* let the kset specific function add its stuff */ 400 if (uevent_ops && uevent_ops->uevent) { 401 retval = uevent_ops->uevent(kset, kobj, env); 402 if (retval) { 403 pr_debug("kobject: '%s' (%p): %s: uevent() returned " 404 "%d\n", kobject_name(kobj), kobj, 405 __func__, retval); 406 goto exit; 407 } 408 } 409 410 /* 411 * Mark "add" and "remove" events in the object to ensure proper 412 * events to userspace during automatic cleanup. If the object did 413 * send an "add" event, "remove" will automatically generated by 414 * the core, if not already done by the caller. 415 */ 416 if (action == KOBJ_ADD) 417 kobj->state_add_uevent_sent = 1; 418 else if (action == KOBJ_REMOVE) 419 kobj->state_remove_uevent_sent = 1; 420 421 mutex_lock(&uevent_sock_mutex); 422 /* we will send an event, so request a new sequence number */ 423 retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum); 424 if (retval) { 425 mutex_unlock(&uevent_sock_mutex); 426 goto exit; 427 } 428 429 #if defined(CONFIG_NET) 430 /* send netlink message */ 431 list_for_each_entry(ue_sk, &uevent_sock_list, list) { 432 struct sock *uevent_sock = ue_sk->sk; 433 struct sk_buff *skb; 434 size_t len; 435 436 if (!netlink_has_listeners(uevent_sock, 1)) 437 continue; 438 439 /* allocate message with the maximum possible size */ 440 len = strlen(action_string) + strlen(devpath) + 2; 441 skb = alloc_skb(len + env->buflen, GFP_KERNEL); 442 if (skb) { 443 char *scratch; 444 445 /* add header */ 446 scratch = skb_put(skb, len); 447 sprintf(scratch, "%s@%s", action_string, devpath); 448 449 /* copy keys to our continuous event payload buffer */ 450 for (i = 0; i < env->envp_idx; i++) { 451 len = strlen(env->envp[i]) + 1; 452 scratch = skb_put(skb, len); 453 strcpy(scratch, env->envp[i]); 454 } 455 456 NETLINK_CB(skb).dst_group = 1; 457 retval = netlink_broadcast_filtered(uevent_sock, skb, 458 0, 1, GFP_KERNEL, 459 kobj_bcast_filter, 460 kobj); 461 /* ENOBUFS should be handled in userspace */ 462 if (retval == -ENOBUFS || retval == -ESRCH) 463 retval = 0; 464 } else 465 retval = -ENOMEM; 466 } 467 #endif 468 mutex_unlock(&uevent_sock_mutex); 469 470 #ifdef CONFIG_UEVENT_HELPER 471 /* call uevent_helper, usually only enabled during early boot */ 472 if (uevent_helper[0] && !kobj_usermode_filter(kobj)) { 473 struct subprocess_info *info; 474 475 retval = add_uevent_var(env, "HOME=/"); 476 if (retval) 477 goto exit; 478 retval = add_uevent_var(env, 479 "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); 480 if (retval) 481 goto exit; 482 retval = init_uevent_argv(env, subsystem); 483 if (retval) 484 goto exit; 485 486 retval = -ENOMEM; 487 info = call_usermodehelper_setup(env->argv[0], env->argv, 488 env->envp, GFP_KERNEL, 489 NULL, cleanup_uevent_env, env); 490 if (info) { 491 retval = call_usermodehelper_exec(info, UMH_NO_WAIT); 492 env = NULL; /* freed by cleanup_uevent_env */ 493 } 494 } 495 #endif 496 497 exit: 498 kfree(devpath); 499 kfree(env); 500 return retval; 501 } 502 EXPORT_SYMBOL_GPL(kobject_uevent_env); 503 504 /** 505 * kobject_uevent - notify userspace by sending an uevent 506 * 507 * @kobj: struct kobject that the action is happening to 508 * @action: action that is happening 509 * 510 * Returns 0 if kobject_uevent() is completed with success or the 511 * corresponding error when it fails. 512 */ 513 int kobject_uevent(struct kobject *kobj, enum kobject_action action) 514 { 515 return kobject_uevent_env(kobj, action, NULL); 516 } 517 EXPORT_SYMBOL_GPL(kobject_uevent); 518 519 /** 520 * add_uevent_var - add key value string to the environment buffer 521 * @env: environment buffer structure 522 * @format: printf format for the key=value pair 523 * 524 * Returns 0 if environment variable was added successfully or -ENOMEM 525 * if no space was available. 526 */ 527 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) 528 { 529 va_list args; 530 int len; 531 532 if (env->envp_idx >= ARRAY_SIZE(env->envp)) { 533 WARN(1, KERN_ERR "add_uevent_var: too many keys\n"); 534 return -ENOMEM; 535 } 536 537 va_start(args, format); 538 len = vsnprintf(&env->buf[env->buflen], 539 sizeof(env->buf) - env->buflen, 540 format, args); 541 va_end(args); 542 543 if (len >= (sizeof(env->buf) - env->buflen)) { 544 WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n"); 545 return -ENOMEM; 546 } 547 548 env->envp[env->envp_idx++] = &env->buf[env->buflen]; 549 env->buflen += len + 1; 550 return 0; 551 } 552 EXPORT_SYMBOL_GPL(add_uevent_var); 553 554 #if defined(CONFIG_NET) 555 static int uevent_net_init(struct net *net) 556 { 557 struct uevent_sock *ue_sk; 558 struct netlink_kernel_cfg cfg = { 559 .groups = 1, 560 .flags = NL_CFG_F_NONROOT_RECV, 561 }; 562 563 ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL); 564 if (!ue_sk) 565 return -ENOMEM; 566 567 ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg); 568 if (!ue_sk->sk) { 569 printk(KERN_ERR 570 "kobject_uevent: unable to create netlink socket!\n"); 571 kfree(ue_sk); 572 return -ENODEV; 573 } 574 mutex_lock(&uevent_sock_mutex); 575 list_add_tail(&ue_sk->list, &uevent_sock_list); 576 mutex_unlock(&uevent_sock_mutex); 577 return 0; 578 } 579 580 static void uevent_net_exit(struct net *net) 581 { 582 struct uevent_sock *ue_sk; 583 584 mutex_lock(&uevent_sock_mutex); 585 list_for_each_entry(ue_sk, &uevent_sock_list, list) { 586 if (sock_net(ue_sk->sk) == net) 587 goto found; 588 } 589 mutex_unlock(&uevent_sock_mutex); 590 return; 591 592 found: 593 list_del(&ue_sk->list); 594 mutex_unlock(&uevent_sock_mutex); 595 596 netlink_kernel_release(ue_sk->sk); 597 kfree(ue_sk); 598 } 599 600 static struct pernet_operations uevent_net_ops = { 601 .init = uevent_net_init, 602 .exit = uevent_net_exit, 603 }; 604 605 static int __init kobject_uevent_init(void) 606 { 607 return register_pernet_subsys(&uevent_net_ops); 608 } 609 610 611 postcore_initcall(kobject_uevent_init); 612 #endif 613